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Topic: 1D X AF in Low Light action (Read 4709 times)

I don't shoot a lot of sports, but I would guess that your choice of lens is most of the problem. Lenses focus at their widest aperture, which means you have a very thin depth of field upon which to lock focus. With moving target, the tiniest of movements will make shots drift away from sharp focus. I know my 85 f/1.2 is VERY finicky and slow about locking focus. That handicap, combined with your low f-stop means you had potentially missed focus lock and a razor thin margin of error once you fired the shot. In your situation, I would have lowered the shutter speed in favor of a higher f-stop. That would give you a little more latitude when the focus wasn't spot on. You also have a ton of choices for AI Servo on the 1DX and you may not have been using the ideal settings for that type of action. I have shot some indoor tennis matches with my 1DX and a 70-200 f/2.8II -- I would imagine that to be even dimmer than your gym (miserable light to play in much less shoot). I was able to keep 1/250 and about f4 for most of the shots. The racquets and balls were frozen, but there was little motion blur with the people. Granted, I only had a single moving subject to lock onto, but the focus tracking stayed spot on. Since I was shooting tennis, I used the AF mode with the little tennis icon and kept it's default settings.

I don't shoot a lot of sports, but I would guess that your choice of lens is most of the problem. Lenses focus at their widest aperture, which means you have a very thin depth of field upon which to lock focus. With moving target, the tiniest of movements will make shots drift away from sharp focus. I know my 85 f/1.2 is VERY finicky and slow about locking focus. That handicap, combined with your low f-stop means you had potentially missed focus lock and a razor thin margin of error once you fired the shot. In your situation, I would have lowered the shutter speed in favor of a higher f-stop. That would give you a little more latitude when the focus wasn't spot on. You also have a ton of choices for AI Servo on the 1DX and you may not have been using the ideal settings for that type of action. I have shot some indoor tennis matches with my 1DX and a 70-200 f/2.8II -- I would imagine that to be even dimmer than your gym (miserable light to play in much less shoot). I was able to keep 1/250 and about f4 for most of the shots. The racquets and balls were frozen, but there was little motion blur with the people. Granted, I only had a single moving subject to lock onto, but the focus tracking stayed spot on. Since I was shooting tennis, I used the AF mode with the little tennis icon and kept it's default settings.

He was shooting at f/2.0, so the front/back focus issue that can come up with the lens stopping down for the shot when it has a very narrow DoF for the AF isn't in play here. It's quite possible it was the extremely bad and crazy lighting in the gym.

Although, somehow my 5d3 managed to lock focus & track when shooting a surfer in a black wetsuit at night next to the Santa Monica Pier with only the shifting light from the ferris wheel, and glowsticks taped to the edge of his wetsuit. It did take a couple of seconds to lock, but once it did it tracked pretty well. Using the 135L @f/2.0 as well come to think of it.

I don't shoot a lot of sports, but I would guess that your choice of lens is most of the problem. Lenses focus at their widest aperture, which means you have a very thin depth of field upon which to lock focus. With moving target, the tiniest of movements will make shots drift away from sharp focus. I know my 85 f/1.2 is VERY finicky and slow about locking focus. That handicap, combined with your low f-stop means you had potentially missed focus lock and a razor thin margin of error once you fired the shot. In your situation, I would have lowered the shutter speed in favor of a higher f-stop. That would give you a little more latitude when the focus wasn't spot on. You also have a ton of choices for AI Servo on the 1DX and you may not have been using the ideal settings for that type of action. I have shot some indoor tennis matches with my 1DX and a 70-200 f/2.8II -- I would imagine that to be even dimmer than your gym (miserable light to play in much less shoot). I was able to keep 1/250 and about f4 for most of the shots. The racquets and balls were frozen, but there was little motion blur with the people. Granted, I only had a single moving subject to lock onto, but the focus tracking stayed spot on. Since I was shooting tennis, I used the AF mode with the little tennis icon and kept it's default settings.

1/250th is not going to work. I won't shoot slower than 1/500th with a 135mm lens. I cannot have motion blur for the type of photography I am shooting.

I think most posters are misunderstanding the problem here, but I thank you for your detailed response because they are valid considerations. The poster helpful is getting what I am saying.

The real issue is the "worse" EV tolerance for AF on the 1DX in high fps vs. less fps or one shot. It makes no sense to argue that it's DOF when 1. In well-lit gyms, I don't have this problem. I have shot hundreds of in-focus photos in a row with the 135L at f/2. 2. I lock focus on shot 1, and it randomly goes in and out of focus throughout the shot burst, annoyingly. For instance, shots 1, 2, 3, 8 are in focus, while shots 4, 5, 6, 7, aren't. This is clearly a low light AF issue with the lens/camera combination and not DOF.

Why would I say that? In enough light, this never happens. In Ashland's gym I shot over 450 photos, all in high burst mode for instance, with the 135L at f/2 and not one was OOF. I have gathered some inside info since my first post that the 1DX in high burst mode is sensitive about -0.5EV whereas about 10 fps and much less it gets better, to -1EV to -2EV. This is the issue I was looking for.

Again, thank you for all who posted or messaged me. I appreciate the help.

It is now 2 months that I own my 1dx + 24-70 f2.8....I have gone through several shoots and lots of Canon pro input(reduce burst, use different cases for AI Servo) in order to get something decent and consistant using 1dx in low light but I have just been disapointed.

The only way I have found to get something better is using "one shot" and snapping faster (as soon as focused is achieved)...

let me tell that it's very frustrating...everytime I read these threads!

but as you all know, once you get to learn the camera's ability you seem to get around it and make the best of it...but having Canon employees telling me that it's normal that it misses some shots ...I beg to differ....never had to even think about missing shots before this.

It is now 2 months that I own my 1dx + 24-70 f2.8....I have gone through several shoots and lots of Canon pro input(reduce burst, use different cases for AI Servo) in order to get something decent and consistant using 1dx in low light but I have just been disapointed.

The only way I have found to get something better is using "one shot" and snapping faster (as soon as focused is achieved)...

let me tell that it's very frustrating...everytime I read these threads!

but as you all know, once you get to learn the camera's ability you seem to get around it and make the best of it...but having Canon employees telling me that it's normal that it misses some shots ...I beg to differ....never had to even think about missing shots before this.

They all have their pros and cons it's just what you can put up with.

I couldn't stand the 1DX/5D3 in terms of low light focussing combined with that af assist issue.

I don't miss my 1DX or 5D3's -- if anything i miss my 7D (ripper of a camera) but since the d4/d800 combo - yes there are a few issues with custom functions not executing and live view is still stuffed (no exp sim on the d4/d800 but the 600 works fine??) but nothing that would stop me from getting my work done.

Canon need to fix a few issues - and its not like we haven't tried to help them (hell we've isolated the issues down to the sequence).

I ask because of something I'm seeing. I bought a 24-70 II and have had somewhat mixed results with it. I've taken some really sharp photos and some (with the similar settings in similar conditions) where the focus point (as determined by DPP) simply isn't sharp.

Thinking back on it, the really sharp ones were all taken in low light at a Christmas party. The others were taken outdoors, but in the shade, so somewhat similar overall illumination. The difference is that Christmas party ones were taken with the battery fully charged. The others were taken a week or so later with the battery at 30% or so.

Not saying there's causation, but I'm looking to explain a few things myself

Though, examining the photos in question again, I see that many of the really sharp ones were also taken in landscape orientation using focus points in the center three "tall" columns. Many of the soft ones were taken with points outside this region.

One of the really soft ones shot in landscape orientation at 1/500 of a sec uses points just to the right of the three tall columns.

Maybe it's time for me to read up on what's expected from the various focus points. I thought the difference was about ability to focus, not quality of it. But I could have that wrong.

Yes, if I remember correctly, the center column (in landscape orientation) is double cross type, with extra sensitive points if used with a compatible lens (I'd be 24-70 v2 and 135L are). Do you have FoCal software? I'm pretty sure you can do a test on all of the AF points to determine which one(s) are reading with high accuracy, and which ones aren't giving as great of accuracy. Something I've been meaning to do, but I'd be it takes quite a while so I haven't taken the time.

The problem is the lens, not the camera. I have found that my 135 f/2 will not focus well in low light no matter what 1 series camera I use it with. My 70-200 f/2.8 IS II is way better than my 135. I shoot dog sports in very low light and the 1Dx works perfectly at 12 fps in light so low you cant read the buttons but it only works this well with one lens - the Canon 200 f/2. Yes, I understand the price tag, but if you want f/2 and fast accurate focusing then this is the lens to use. It is twice as accurate as my 70-200 so you can imagine how much better it is than the 135 f/2.

Here is a shot in very, very low light (we refuse to shoot there now) where the 1Dx with a 200 f/2 hits the focus without issue. Sorry this is a processed image but the original looks very good and is sharp. The high ISO softens it a bit, but the auto focus hit perfectly and the numbers on the stickers on the shirt were sharp. I actually added grain to this processed image to match the retro color processing. Note: that dog is super fast and runs 7 yards per second!

I do have the software and I will check it out (probably won't find the time until next weekend, though).

To Studio1930's point, I've never had an issue with my 70-200 II in low light -- even inside an ice rink. Kind of sad to see the issue with the 24-70 II. Though, I will say that I have used the 24-70 II at night on a moving train and still gotten fairly good pictures (at 1/200 sec with a more fully charged battery).